1. Field of the Invention
The present invention relates to a four-stroke engine, and more particularly to a four-stroke internal combustion engine with an oil spray generating assembly to produce oil spray for lubrication.
2. Description of Related Art
Four-stroke internal combustion engines were developed over one hundred years ago, to power machines that do a specific job and comprise a block, a cylinder, a piston, a crankcase and a cylinder head. The cylinder is formed in the block. The piston is movably mounted and moves reciprocally in the cylinder and has a piston head and a connecting rod. The connecting rod has a top end and a bottom end, and the top end is pivotally connected to the piston head. The crankcase is attached to the block and includes a bottom, a crankshaft and an oil pan. The crankshaft is rotatably mounted in the crankcase, and the bottom end of the connecting rod is attached rotatably to the crankshaft. Therefore, the reciprocating motion of the piston in the cylinder causes the crankshaft to rotate. The oil pan is a reservoir to hold lubricating oil and is attached to the bottom of the crankcase.
However, friction is created during the operation of the piston and the crankshaft. The friction generates heat that will cause the engine to breakdown unless the friction and resultant heat are limited. Lubrication of the piston and the crankshaft in the engine is the most important means of limiting friction and the resultant heat when the engine is running. Lubricants such as lubricating oil are extensively used to lubricate moving parts in an engine. A forced lubrication system in an engine uses lubricating oil spray or vapor in addition to the lubricating oil to lubricate moving parts in an internal combustion engine.
A conventional method to produce the oil vapor uses an agitating rod or slinger ring to agitate the lubricating oil in the oil pan. The agitating rod is attached to the bottom end of the connecting rod and rotates with the crankshaft. The rotation of the agitating rod agitates the lubricating oil in the oil pan and generates an oil vapor for lubrication. However, the oil pan must be large enough to accommodate the agitating rod used to agitate the oil. Specifically, the oil pan must have a depth greater than the combined length of the agitating stick and the offset of the crank on the crankshaft.
Furthermore, the exhaust in the exhausting stroke of the engine contains water vapor and lubricating oil droplets in addition to other exhaust gases. If the water vapor is not separated from the lubricating oil droplets, the lubricating oil droplets will be recycled with water vapors, and the water vapors will rust or oxidize the engine.
To overcome the shortcomings, the present invention provides a four-stroke internal combustion engine with an oil spray generating assembly and an oil recycling assembly to mitigate or obviate the aforementioned problems.
The main objective of the invention provides a four-stroke internal combustion engine with an oil spray generating assembly, which has a simple feature to produce oil vapor or spray for lubrication.
Also, another objective of the invention is to provide a four-stroke internal combustion engine with an oil recycling assembly that will separate oil droplets and water vapor, and collect the separated lubricating oil and recycle the lubricating oil to the oil pan of the engine.
Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.